The present invention relates to a refrigerating apparatus and more particularly to food product chillers of the type employing cooled, hygroscopic liquid refrigerant.
In various food processing operations, it is necessary that the food product be chilled or surface frozen to preserve the color and appearance of the products after initial preparation. For example, in the processing of poultry it has been common practice to quick freeze the poultry parts and/or whole poultry carcasses after dressing. Also, in the processing of meat products such as sausage, the product may be frozen after wrapping in the casing. Such quick freezing has typically been accomplished with chillers which include some form of conveyor for transporting the product through an enclosure. When the product is within the enclosure, it is contacted by sprays or streams of cooled, liquid refrigerant such as propylene glycol. A distribution system is provided so that the glycol is directed downwardly within the enclosure, collected at the bottom of the enclosure, passed through a suitable heat exchanger and recirculated to pass through the enclosure again.
An example of one such prior chiller may be found in U.S. Pat. No. 3,315,489, entitled POULTRY FREEZING APPARATUS OF THE LIQUID SPRAY TYPE, and issued on Apr. 25, 1976 to R. S. Zebarth et al. The chiller disclosed in this prior patent includes at least a pair of vertically spaced, horizontally extending belts. The belts are positioned within an enclosure having entrance openings at one end and exit openings at the opposite end. A liquid refrigerant distribution system is supported within the enclosure above the belts. The poultry product is placed on the belts at one end of the enclosure and is contacted by streams or sprays of the liquid refrigerant as it passes from one end of the enclosure to the opposite end of the enclosure. The liquid refrigerant, which contacts the uppermost of the belts within the enclosure, is collected and passed downwardly to contact the belt positioned therebelow.
Another example of a chiller apparatus employing a liquid refrigerant may be found in U.S. Pat. No. 2,200,331, entitled AN APPARATUS FOR FREEZING BERRIES, and issued on May 14, 1940 to H. R. Fisher. The apparatus disclosed in this latter patent does not employ a conveyor but does, however, use a cooled liquid refrigerant to chill food product such as berries and other similar vegetable products.
Heretofore, the prior liquid chillers, although operating to obtain the desired results have had certain inherent drawbacks relating to the amount of floor space required in a plant for such apparatus, the length of residence time of the food product within the enclosure of the apparatus to obtain the desired cooling and other disadvantages relating to efficiency of operation.
A need exists for an improved apparatus for chilling edible food products, such as sausage, whereby increased efficiency may be obtained, the floor space requirements may be reduced and/or increased product handling rates may be obtained and desirable cost economies may be achieved.